Hydraulic problem on 1974 Mercury 115.

[TimDollar]

I just bougt a boat that has not been in the water for a while. I got the motor working but the Hydralic lift is not workworking. It does not even make a noise. I checked and it is getting power to the solenoid but nothing. Any suggestions? Also what is the red rubber plug that has 3 slots for?

 

[Texasmark]

Re: Hydraulic problem on 1974 Mercury 115.

Getting power out of the solenoid? Getting power to the control windings of the solenoid when you push the tilt button?

Not familiar with yours but some come with a bypass screw so that you can manually lift the engine. As I recall you turn it 90 degrees for bypass.

Then there should be a screw about half inch in dia that is for fluid. On your older unit I think they used 30 wt oil.

HTH, best I can do.

Mark

 

[Chris1956]

Re: Hydraulic problem on 1974 Mercury 115.

Tim, The red plug is connected to three wires that constitute the wiring harness of the PTT system. On wire is for power to the PTT control panel (three switches on the dashboard) the other two are for power from the control panel to the pump. You need to have power on the secondary winding of the solenoid (two small terminals, one is grounded), for the solenoid to close and cause the pump to run in the up direction. Best bet is to jumper from the battery side of the solenoid to the green wire (pump should run in one direction), and then the blue wire (pump should run the other way) to check out the pump motor. There is no solenoid for trimming down.

PS the aluminum slotted screw on the pump is the fill. Use SAE 5W-30 oil. There is a trim limit switch on the starboard trim cylinder bracket. Thes go bad, and can be bypassed (find the purple wire in the wiring harness).